1. Field of the Invention
This invention relates to a rotatable tube cutter. More specifically, the invention relates to a rotatable tube cutter for cutting metal tube or the like. It is easy to operate by one hand. It is able to work in a limited space. It is possible to work by the traditional full circle rotation method. Plus, it has manual and automatic dual feeding modes.
2. Description of the Prior Art
A metal tube can be cut by many methods. If this metal tube is movable and made by a harder metal like steel, usually it can be cut by a saw or by a traditional cutting machine. But, if the tube is fixed on the wall of a building, especially for the copper tube of ventilation and heater systems, the user will face the following problems:
First, the work piece (the copper tube) is fixed near the corner of the ground (or ceiling) and the wall. In this case, not only the work piece cannot move, but also the available space around the work piece is quite limited. The user only can bring a hand tool to cut this fixed work piece. However, if the user wants to rotate the hand tool to cut it, there must be a larger space.
Second, such work piece made by copper is softer than steel""s one. It is easy to deform. If a small area of the work piece is hit or punched by an unintentional heavy force, the work piece will deform immediately. Once the cutting edge of work piece is deformed (become non-circular), it cannot connect with other tube that has a circular edge. That means it becomes useless. Therefore, it is impossible to cut the work piece by using a traditional cutting tool.
Referring to FIGS. 1 and 2, a work piece 80 (a thin copper tube) is fixed on a wall of a building. Under such limited space, only a traditional mini tube cutter 90 can be used. This portable mini tube cutter 90 mainly comprises a fixing base 91, a movable base 92 that can slide on the fixing base 91, and a rotatable knob 93 that can control the position of the movable base 92. The fixing base 91 has two rolling elements 911. A cutting wheel 921 is disposed on the movable base 92. When the user rotates the rotatable knob 93, the work piece 80 will be sandwiched by these two rolling elements 911 and the cutting wheel 921. Then, the user rotates the entire mini tube cutter 90 for a circle (rotating 360 degrees). One hand of the user can hold the mini tube cutter 90 and the other hand""s fingers of the user can force the rotatable knob 93 rotating in order to feed the cutting wheels 921 in. After which, the user continues to rotate it. Just repeating the above-mentioned steps, the work piece 80 will be cut eventually. Its cutting edge remains circular, so this work piece 80 still can be used for connecting other tube or device.
However, if the user operates this kind of mini tube cutter 90 for a long time, the fingers might be injured. For a harder work piece, the user has to apply larger force via fingers. Under such circumstance, it is very hard to rotate or it cannot rotate. This will cause another problem.
In addition, if the size.of the work piece 80 is too large, there will be no mini tube cutter 90 available. The user has to use other type heavy and complex manual tube cutter (sot shown), but it needs a larger space around the work piece 80 for rotating operation. Otherwise, the user must detach the work piece 80 and then brings it down to a cutting machine somewhere. Thus, larger work piece 80 will cause many other problems.
Therefore, the inventor utilizes the basic principle from the switchable ratchet wrench 95 (shown in FIG. 3) into the existing mini tube cutter 90. Then, a new product is invented in order to solve above-mentioned problems.
It is a principal object of the present invention to provide a rotatable tube cutter. By utilizing the fixing portion, rotatable portion, cutting blade assembly, and feeding assembly, this invention is easy to operate by one hand.
It is another object of the present invention to provide a rotatable tube cutter that is able to work in a limited space.
It is still another object of the present invention to provide a rotatable tube cutter that is also possible to work by the traditional full circle rotation method.
It is one more object of the present invention to provide a rotatable tube cutter. In which, it has dual feeding modes, namely the manual feeding mode and the automatic feeding modes. In operation, it is more convenient.